URL querystring not parsed correctly in 0.7.0

It seems that since upgrading to 0.7.0, drf-flex-fields no longer parses expansions requested via URL querystring the same way.

I have been doing this:

class EphemeronViewSet(FlexFieldsModelViewSet):
    [...]
    def get_serializer(self, *args, **kwargs):
        if "expand" in self.request.query_params:  # add from querystring in URL
            kwargs["expand"] = self.request.query_params['expand']
        return super(EphemeronViewSet, self).get_serializer(*args, **kwargs)

which allows expanding fields like this:

curl '0.0.0.0:8000/api/ephemera/?expand=user'

But since upgrading to 0.7.0, the field no longer gets expanded in the output.

I think these changed lines are what resulted in the change in behavior. If I add a print(passed) just after that and compare previous behavior to 0.7.0:

Before:

{'expand': 'user', 'fields': [], 'omit': []}

After:

{'expand': ['u', 's', 'e', 'r'], 'fields': [], 'omit': []}

Perhaps these lines should be something more like [kwargs.pop("expand")] if "expand" in kwargs else [] instead of list(kwargs.pop("fields", []))?

(Or perhaps there's a better way to pass querystrings to drf-flex-fields than what I've been doing in my get_serializer() override as shown above? I have been doing it that way in order to expand fields in response to a POST request, if I recall recorrectly.)

Thanks, I'm looking into this.

I appreciate the detailed issue. Yes, I agree that those changes lines are responsible. Before, it seems like things worked when you passed a string value for expand when constructing a serializer:

serializer = EphemeronSerializer(object, expand='user')

As I understand from your issue, this used to work. However, I did not intend to support passing strings to the keyword serializer options (expand, fields, omit). Ensuring that you pass a list for the expand value should fix this for you.

serializer = EphemeronSerializer(object, expand=["user"])

But ... what you are doing in the get_serializer method may not be necessary because this package will automatically read the expand value from request's query params (if it is not passed explicitly as a kwarg to the constructor):

drf-flex-fields/rest_flex_fields/serializers.py

Line 226 in cef061c

expand = self._parse_request_list_value("expand")

I see! I'll look into other ways of expanding fields in response to POST requests. I see it was discussed on #25.

Thanks, feel free to close!

Ah I see. Yes, I should revisit that issue.